Needling machines are generally well known in the prior art and are described in, for example, Vliesstoffe [Nonwovens] by Lünenschloss and Albrecht, Georg-Thieme-Verlag, Stuttgart, 1982, pp. 122-129.
In needling machines, a nonwoven is usually supplied to the inlet of the machine and conveyed to the needling zone. A needle bar, to which a needle board is fastened, is arranged in the area of the needling zone. The needle board is equipped with needles for consolidating the nonwoven. In this area, the nonwoven to be needled is guided between a stripper plate and a stitching plate. The needles consolidate the nonwoven as they are punched into the nonwoven and pulled back out again at high frequency. As this is being done, the needles pass through openings in the stripper plate and stitching plate. The resulting product is a consolidated nonwoven. The expert is familiar with the various types of needling machines, including double-needle machines, in which two needle bars are used for needling, one from above, the other from below, and needling machines in which the needle bars are moved along in the direction of the nonwoven during the consolidation process.
U.S. Patent Application No. 2010/0162543 discloses a needle board for needling machines which comprises a plurality of needle modules, each of which comprises a carrier plate, equipped with a plurality of needles. The individual needles are mounted in the carrier plate of the needle module by injection-molding or casting. The needle modules are set into slots in a base plate of the needle board. Through the use of needle modules in a needle board, it has become possible to refit needle boards quickly and easily and to prolong the life of the needle boards, because there is no longer any need for the individual bores in the needle board into which the individual needles fit, and the wear to which these bores are subject during the replacement or exchange of the individual needles is no longer a concern. The arrangement of the individual needle modules in the needle board and the arrangement of the individual needles with respect to each other within a needle module, however, are fixed and cannot be varied. If the needling of the nonwoven is now to be carried out with a different pattern or if an adaptation of the needle arrangement or spacing of the needles is desired to homogenize the stitching pattern or to compensate for defects, individualized needle modules and needle boards must be kept on hand for all possible arrangements which can come into question, and, when necessary, the modules and boards must then be exchanged at the cost of considerable effort.
It is an object of the present invention to provide a needle module for a needle board of a needling machine in which the spacing and the arrangement of the individual needles with respect to each other are variable.